Eurydice mohani, Anil & Jayaraj, 2023

Anil, Pathan & Jayaraj, K. A., 2023, Two new species of Eurydice Leach, 1815 (Crustacea: Isopoda: Cirolanidae) from the Andaman Islands, northern Indian Ocean, Journal of Natural History 57 (13 - 16), pp. 976-995 : 986-993

publication ID	https://doi.org/ 10.1080/00222933.2021.2017046
DOI	https://doi.org/10.5281/zenodo.8202255
persistent identifier	https://treatment.plazi.org/id/0217CC2F-463F-3859-8E93-FF17FF28FD09
treatment provided by	Plazi
scientific name	Eurydice mohani
status	sp. nov.

Treatment

Eurydice mohani View in CoL sp. nov.

( Figures 6–9 View Figure 6 View Figure 7 View Figure 8 View Figure 9 )

Material examined

Holotype. Male (3.5 mm), sta. Corbyns Cove (low-tide zone), 11.37′483°N, 92.45′140°E, South Andaman , Andaman Islands, intertidal sand, coll. Pathan Anil, 18 November 2016 (Reg. no. PUMB 3585 ).

Paratypes. 1 male (3.4 mm), 3 females (3.3, 3.4, 3.4 mm), same data as holotype (Reg. no. PUMB 3586 ) . 1 male (3.4 mm), 2 females (3.3, 3.4 mm): sta Marina Park (low-tide zone), 11.40′18°N, 092.44′58°E, South Andaman, Andaman Islands, intertidal sand, coll. Pathan Anil, 9 December 2016 (Reg. no. PUMB 3587 ; Reg. no. BAKRZRL 2704 , 2705 ) GoogleMaps .

Description of male holotype. Body about 2.3 times as long as greatest width; maximum width at pereonites 4 and 6. Cephalon anterior median margin weakly produced, with minute rostral point. Eyes prominent. Coxae 2–3 posteriorly sub-acute with minute setae, posterolateral angles of coxae 6–7 acute with minute setae, not produced. Pleonite 1 concealed by pereonite 7, ventral margins of pleonites 2–4 produced with acute points. Pleotelson about 82% as long as pleon in lateral view; lateral distal margins are sinuate; pleotelson posterior margin 20% of pleotelson anterior width, convex, subtruncate with 6 PMS and 4 RS, dorsally with minute thin setae; anterodorsal surface without distinct depression.

Antennula peduncle article 1 anteriorly with 1 simple, 1 pappose setae; article 2 slightly shorter (0.83 times) than 3; article 2 posterodistal angle with 2 simple, 1 pappose setae, anterodistal angle with 1 simple seta; article 3 anterodistal angle with 4 simple short setae; flagellum about 0.8 times as long as peduncle, with 5 articles, article 1 of which is longest, about 1.7 times as long as article 2; flagellum extending to anterior of pereonite 1. Antenna peduncle article 1 dorsal posterior margin with 1 seta, article 2 anterodistal angle with 2 slender simple setae; article 3 short and wide, about 0.9 times as long as wide and about 1.5 times as long as article 2, anterior margin with 8 simple long setae, posterior distal margin with 1 simple long seta; article 4 longest about 2.3 times as long as 3, anterior margin with 4 clusters of 2, 2, 2 and 2 simple long setae, posterior margin with 3 long simple setae and 1 brush-tipped seta; flagellum extending to mid-pereonite 5, composed of about 12 articles.

Frontal lamina distinct; clypeus blade prominent. Mandible spine row with 7 spines; molar process anterior margin with about 21 teeth; article 2 with 4 simple long setae; article 3 apically with 3 simple long setae. Maxillule lateral lobe with 12 RS, medial lobe with 3 CPS and 1 simple seta. Maxilla lateral lobe with 3 stiff simple setae, middle lobe with 5 weakly serrate setae, medial lobe with 5 simple setae and 3 CPS. Maxilliped article 2 medial distal margin with 5 long setae, lateral margin with 1 long seta; article 3 medial distal margin with 4 long setae, lateral margin with 1 long seta; article 4 medial distal margin with 4 long setae, lateral margin with 1 long seta; article 5 apically 6 long setae; endite with 1 CPS and 3 simple setae.

Pereopod 1 basis 3.3 times as long as greatest width, superior proximal margin with 3 small sensory palmate setae, distal margin with 3 long setae, inferior margin with 10 long setae; ischium 0.7 times as long as basis, superior distal margin with 8 long setae, dorsal posterior margin with 3 long setae, inferior margin with 8 long setae; merus inferior margin with 3 RS and 7 long setae, dorsal medial margin with 2 simple long setae and 1 short RS, superior distal margin with 6 long setae; carpus inferior margin with 1 RS and 6 simple long setae; propodus 3.8 times as long as width, inferior margin with 3 RS and 9 long setae; dactylus about half as long as propodus, robust seta opposing dactylus extending to accessory unguis; accessory unguis slender, 0.8 times length of unguis.

Pereopod 2 basis about 3.9 times as long as wide, superior margin with 3 small sensory palmate setae, inferior distal angle with 18 long setae; ischium 2.2 times as long as basis, inferior margin with 2 RS and 11 long setae,dorsal posterior margin with 4 long setae,superior distal margin with 8 long setae; merus inferior margin with 5 RS and 9 long setae, superior distal angle with 8 long setae; carpus inferior distal angle with 2 RS and 5 long setae;propodus 4.1 times as long as width, inferior margin with 3 RS and 8 long setae, dorsal posterior margin with 1 short RS; dactylus about half as long as propodus; robust seta opposing dactylus extending to accessory unguis; accessory unguis 0.9 times length of unguis.

Pereopod 3 basis superior margin with 3 small sensory palmate setae, inferior margin with 13 long setae; ischium inferior margin with 2 RS and 12 long setae, dorsal medial margin with 5 long setae, superior distal angle with 9 long setae; merus inferior margin with 6 RS and 9 long setae, superior distal angle with 7 long setae; carpus inferior distal angle with 2 RS and 5 long setae; propodus inferior margin with 3 RS and 10 long setae; dactylus less than half as long as propodus; robust seta opposing dactylus extending near to accessory unguis. Pereopods 5–7 similar to each other.

Pereopod 6 basis 5.6 times as long as wide, superior margin with 2 small sensory palmate setae and 6 long setae, inferior margin with 13 long setae; ischium 0.8 times as long as basis, inferior margin with 15 RS and 11 long setae, superior margin with 4 RS and 11 long setae; merus 0.5 times as long as ischium, 1.8 times as long as wide, inferior margin with 5 RS and 2 long setae, superior margin with 4 RS and 7 long setae; carpus 0.9 times as long as ischium, 2.5 times as long as wide, inferior margin with 6 RS, 1 uni-serrate seta and 1 long seta, superior margin with 5 RS, 1 uni-serrate seta and 4 simple long setae; propodus 0.6 times as long as ischium, 4.9 times as long as wide, inferior margin with 10 RS and 2 long setae, superior margin with 5 RS and 4 long setae; dactylus 0.6 times as long as propodus.

Pereopod 7 basis 5.8 times as long as wide, superior margin with 4 small sensory palmate setae and 3 long setae, inferior margin with 10 long setae and 1 long uni-serrate seta; ischium 0.9 times as long as basis, inferior margin with 7 RS and 11 long setae, superior margin with 3 RS and 9 long setae; merus 0.7 times as long as ischium, 1.9 times as long as wide, inferior margin with 4 RS, 3 bi-serrate setae and 3 long setae, superior margin with 2 bi-serrate setae, 1 RS and 5 long setae; carpus 0.9 times as long as ischium, 2.7 times as long as wide, inferior margin with 6 RS, 1 bi-serrate seta and 6 long setae, superior margin with 7 RS, 1 uni-serrate seta and 4 long setae; propodus 0.8 times as long as ischium, 5.1 times as long as wide, inferior margin with 14 RS and 1 bi-serrate seta, superior margin with 10 RS and 8 long setae.

Penes 1.6 times as long as basal width, distal margin rounded.

Pleopod 1 exopod 1.6 times as long as wide, lateral margin weakly convex, distally narrowly rounded with oblique medial margin, mesial margin strongly convex, with PMS from distal one-fourth, with 20 PMS; endopod 2.2 times as long as wide, distally narrowly rounded, lateral margin weakly convex, with PMS from distal one-third, mesial margin with PMS from distal one-sixth, endopod with 10 PMS; peduncle 0.8 times as wide as long, mesial margin with 4 coupling setae, 2 plumose setae and 1 short setae. Pleopod 2 exopod with 20 PMS, endopod with 9 PMS; appendix masculina arises from medial margin of the endopod, lateral margin with a sinuate notch and apex is rounded, appendix masculina 0.4 times as long as endopod, projecting beyond mid-region of endopod by 0.02 of its length. Pleopod 3 exopod with 20 PMS, endopod with 9 PMS. Pleopod 4 exopod with 24 PMS, endopod with 8 PMS. Pleopod 5 exopod with 22 PMS. Pleopods 3–5 exopods with complete sutures.

Uropod peduncle lateral margin with 5 stiff PMS and 1 RS; exopod rounded, about 0.9 times as long as length of endopod lateral margin, medial margin with about 12 PMS and 3 RS; endopod lateral margin straight, with 2 setae, medial margin obliquely truncate, with 2 small RS and 20 PMS.

Female. As for male but body slightly broader, about 1.5 times as long as greatest width; antennulae shorter reaching mid-region of the eye; antennae shorter, reaching posterior margin of pereonite 4; pleotelson about 80% as long as pleon in lateral view.

Colour. Body white; black chromatophores occur densely on the dorsal surface of the pereion, pleon and pleotelson.

Remarks. Eurydice mohani sp. nov. can be identified by the pleotelson posterior margin being 20% of pleotelson anterior width, with 6 plumose marginal setae, anterodorsal surface without distinct depression; appendix masculina 0.4 times as long as endopod, projecting beyond mid-region of endopod by 0.02 of its length, lateral margin with a sinuate notch and apex is rounded; the antennal flagellum is relatively short, extending to mid-length of pereonite 5.

Eurydice mohani sp. nov. is separated from Eurydice andamanensis sp. nov. by the antennula flagellum extending to anterior of pereonite 1 (vs posterior of pereonite 1), posterior margin of pleotelson one-fifth of pleotelson anterior width, with 6 plumose marginal setae (vs one-fourth and 11 plumose marginal setae), pleotelson anterodorsal surface without distinct depression (vs distinct depression), appendix masculina lateral margin with a sinuate notch (vs lacking), appendix masculina 0.4 times as long as endopod, projecting beyond mid-region of endopod by 0.02 of its length (vs 0.8 long as endopod, projecting slightly beyond by one-third of its length), uropodal exopod medial margin rounded (vs obliquely subtruncate).

Eurydice mohani sp. nov. is similar to Eurydice barnardi Bruce and Soares, 1996 , which was described from the Atlantic coast of South Africa and shares some characters such as cephalon anterior median margin with minute rostral point, coxae 2–3 posteriorly sub-acute, posterolateral angles of coxae 6–7 acute, not produced, and pleotelson anterodorsal surface without depression, but E. mohani sp. nov. differs from E. barnardi in the pleotelson posterior margin 20% of width (vs 5% of width), pleotelson posterior margin with 4 robust setae and 6 plumose marginal setae (vs 2 robust setae and 3 plumose marginal setae), appendix masculina lateral margin with sinuate notch (vs lacking).

Eurydice mohani sp. nov. can be separated from Eurydice indicis by convex pleotelson posterior margin, with 6 plumose marginal setae (vs straight with 8 plumose marginal setae), pleotelson anterodorsal surface without distinct depression (vs distinct depression), appendix masculina lateral margin with sinuate notch (vs lacking notch).

Eurydice mohani sp. nov. also differs from Eurydice peraticis in pleotelson posterior margin convex with 6 plumose marginal setae (vs almost straight with 13 plumose marginal setae), appendix masculina lateral margin with sinuate notch (vs lacking notch).

Distribution. Known only from the type locality: South Andaman, Andaman Islands.

Etymology. This species is named in honour of Dr P.M. Mohan, Professor, Department of Ocean Studies and Marine Biology, Pondicherry Central University, the DC member of the first author (Pathan Anil) and a well-known benthologist, taxonomist and ecologist in India.